1. Field of the Invention
The present invention relates to a hyperfrequency device having at least one triple plate line and at least one passive limiter formed by two diodes connected electrically in series, the suspended line between the two ground planes of the triple plate line forming a common point for the diodes.
The invention has been designed so that the diodes are readily accessible when the device is mounted in complex hyperfrequency equipment, and for this purpose the diodes are mounted on the same side of the suspended line.
2. Discussion of the Background
So that the description of the invention is clear, the example of a power limiter will be chosen for explaining the text and the figures, without this limiting the scope of the invention which concerns any device in which two series diodes are mounted on each side of a triple plate line, from an electrical point of view. In fact, depending on the chosen configuration, the device of the invention is a power limiter, or a power phase shifter or, if the diodes are biased, a switch.
The term triple plate line is given to an element for the propagation of a hyperfrequency wave, in which a metal line is suspended in a dielectric medium, which may be air or a solid dielectric, between two ground planes situated on each side of the suspended metal line. A triple plate line acts, in the hyperfrequency circuit field, in a way comparable to coaxial lines.
It is known that two series diodes, mounted between a first ground plane, with the suspended line as a common point for both diodes, and a second ground plane, operate as a limiter and provide satisfactory performance from an electrical point of view. However, if a limiter mounted in complex equipment is considered it is apparent that for mounting, adjusting and maintaining the limiter it is not convenient to have diodes which are situated on both sides of the suspended line. If it is necessary for example to have access to one or more diodes, the whole triple plate line must be dismantled, which is often badly placed from a mechanical point of view, against a wave guide or a circulator, and which is not readily accessible.
The invention provides a solution to the problems of accessibility and the maintenance of a power limiter.